Adjuvant chemotherapy with S-1 followed by docetaxel for gastric cancer and CY1P0 peritoneal metastasis after relatively curative surgery

The survival and prognosticators of peritoneal cytology-positive gastric cancer patients who received upfront gastrectomy and subsequent S-1 chemotherapy

BACKGROUND

Upfront surgery and subsequent S-1 chemotherapy is frequently selected for peritoneal cytology-positive (CY1) gastric cancer patients without other distant metastases (CY1-only). The objective of this study was to confirm the efficacy of this strategy in clinical practice and to identify the risk factors associated with survival.

METHODS

Overall survival (OS) and recurrence-free survival (RFS) were examined in 36 CY1-only patients who underwent macroscopic curative resection followed by postoperative S-1 chemotherapy between January 2000 and June 2015. Univariate and multivariate analyses were performed using a Cox proportional hazards model to identify risk factors.

RESULTS

The median OS was 22.3 months (95% confidence interval 18.7-31.0). When the OS was compared by a log-rank test, significant differences were observed in the status of lymph node metastasis of pathological N3b (pN3b). Moreover, the univariate and multivariate analyses demonstrated that the status of pN3b was a significant independent risk factor for OS and RFS. The median OS in patients with pathological N0-N3a (pN0-N3a) was 31.0 months, while that in patients with pN3b was 18.2 months (P = 0.002). The median RFS in patients with pN0-N3a was 16.4 months, while that in patients with pN3b was 7.9 months (P = 0.007).

CONCLUSIONS

The present study confirmed the efficacy of postoperative S-1 chemotherapy for CY1-only gastric cancer patients who received upfront surgery. This strategy might be recommended as clinical practice for patients with CY1 disease but a more effective treatment should be established for CY1-positive patients, especially for those who are diagnosed with CY1 and pN3b disease.